Quoting Michael K.
This would be bad. What if someone went back and killed someone important and so something important never happened? I think it's impossible.

There is the minor fact that you'd never know, since the thing wouldn't have happened at all.

There's various theories, and as usual for metaphysics, there's no way to prove any of them.

Quoting Achintya Prasad
Well, I mean, theoretically, if you exceed the speed of light, you are kinda time traveling. But really, supposing its possible, it leaves a lot of conundrums. I say leave it alone!

I believe it is possible by high accelerations (not speeds) to travel in time, but it is unpredictable and possibly dangerous without bending time-space continuum yourself.

As for changing history, you have to know it has already been attempted. If time travel will ever be invented.

Time is pre-determined IF it exists at all. It could be linear, but in an existing time system, I prefer the possibility of multi-dimensional time that would make an illusion of randomness and free will.Permalink

Quoting Deus "Big D." Otiosus
I believe it is possible by high accelerations (not speeds) to travel in time, but it is unpredictable and possibly dangerous without bending time-space continuum yourself.

As for changing history, you have to know it has already been attempted. If time travel will ever be invented.

Time is pre-determined IF it exists at all. It could be linear, but in an existing time system, I prefer the possibility of multi-dimensional time that would make an illusion of randomness and free will.

But HOW would someone go about travel into the past or future?Permalink

Quoting Deus "Big D." Otiosus
I believe it is possible by high accelerations (not speeds) to travel in time, but it is unpredictable and possibly dangerous without bending time-space continuum yourself.

As for changing history, you have to know it has already been attempted. If time travel will ever be invented.

Time is pre-determined IF it exists at all. It could be linear, but in an existing time system, I prefer the possibility of multi-dimensional time that would make an illusion of randomness and free will.

But HOW would someone go about travel into the past or future?

I have yet to connect information and acceleration, but there is a top limit for sure. When reached, it should turn someone in more than three dimensions. Also non-euclidian space.

There's a pretty good short story called "A Sound of Thunder" by Ray Bradbury. It doesn't really have anything to do with HOW they accomplish time travel, but it has some pretty interesting ideas for the consequences of time travel.Permalink

Does it count as messing up time if you go forwards in time and change something? While it seems like stuff in the future hasn't happened yet, and thus time travellers would merely shape the future, we must recall that time is considered the fourth dimension and thus is a plane on which all time occurs at once. Hence, the future is happening right now, and changing it would actually create paradoxes that we're unawares of.

That said, I'd love to travel in time - but if it were so readily available then everyone would do it and mess all sorts of stuff up.Permalink

Quoting Deus "Big D." Otiosus
I have yet to connect information and acceleration, but there is a top limit for sure. When reached, it should turn someone in more than three dimensions. Also non-euclidian space.

Interesting theory. If someone attained four dimensionality, would they essentially be able to walk through time?Permalink

Quoting LukeClarenceVan The Revanchist
Does it count as messing up time if you go forwards in time and change something? While it seems like stuff in the future hasn't happened yet, and thus time travellers would merely shape the future, we must recall that time is considered the fourth dimension and thus is a plane on which all time occurs at once. Hence, the future is happening right now, and changing it would actually create paradoxes that we're unawares of.

Time is a single dimension, so not really a 'plane', but it's true, time traveling into the future would have no causal contradictions.

Quoting LukeClarenceVan The Revanchist
That said, I'd love to travel in time - but if it were so readily available then everyone would do it and mess all sorts of stuff up.

Quoting LukeClarenceVan The Revanchist
Does it count as messing up time if you go forwards in time and change something? While it seems like stuff in the future hasn't happened yet, and thus time travellers would merely shape the future, we must recall that time is considered the fourth dimension and thus is a plane on which all time occurs at once. Hence, the future is happening right now, and changing it would actually create paradoxes that we're unawares of.

That said, I'd love to travel in time - but if it were so readily available then everyone would do it and mess all sorts of stuff up.

Since it's the past causing something to happen in the future, I think we would be clear of any paradoxical situations, but if every moment of time is in constant existence, then changing something about our future is changing something in someone else's past. Doc Brown would disapprove;)Permalink

Quoting Bob the inconceivably invincible
Time is a single dimension, so not really a 'plane', but it's true, time traveling into the future would have no causal contradictions.

Ah yes... I must ponder this a bit then. If it's a single dimension, then it forms a line on which we can move backwards or forwards at a pace determined by out speed/acceleration. Thus, in order to time travel we must drastically change our speed/acceleration, or access the fifth dimension - thus forming a plane and allowing us to move outside of the constraints of linear time.Permalink

Quoting Tim C
Since it's the past causing something to happen in the future, I think we would be clear of any paradoxical situations, but if every moment of time is in constant existence, then changing something about our future is changing something in someone else's past. Doc Brown would disapprove;)

However, if time travel was possible, how could we know about it? And if things were to change, we may not know, as it was already changed but because it was already changed it never REALLY changed as nobody would know what it changed from. So it may as well have not changed at all. People often say they wish they could go back and change the past to prevent things from happening, but it always leads to those paradoxes or whatever you wish to term them, as if you had changed the past, there would be no past to change. And if someone had, you would never know as it was already changed and how it is currently is how it always was and shall be. Anything that can happen does happen. Humans have a natural desire to want to explore and find answers because there are so many questions to be asked. But I believe that there are so many things that are merely beyond our cognitive capacity, but we are intelligent enough to understand the concept, just not the execution. And I think time travel is one of those things. And I think that even if we were provided with the tools to make time travel possible, it's not the place of humans to attempt something, and for all we know that has happened in the future and the human that was introduced to it had the brains to destroy it. There are infinite possible explanations but we could be here all day for that. We should always question things, but just because we could, doesn't mean we should. Permalink

Quoting Josh B.
However, if time travel was possible, how could we know about it? And if things were to change, we may not know, as it was already changed but because it was already changed it never REALLY changed as nobody would know what it changed from. So it may as well have not changed at all. People often say they wish they could go back and change the past to prevent things from happening, but it always leads to those paradoxes or whatever you wish to term them, as if you had changed the past, there would be no past to change. And if someone had, you would never know as it was already changed and how it is currently is how it always was and shall be. Anything that can happen does happen. Humans have a natural desire to want to explore and find answers because there are so many questions to be asked. But I believe that there are so many things that are merely beyond our cognitive capacity, but we are intelligent enough to understand the concept, just not the execution. And I think time travel is one of those things. And I think that even if we were provided with the tools to make time travel possible, it's not the place of humans to attempt something, and for all we know that has happened in the future and the human that was introduced to it had the brains to destroy it. There are infinite possible explanations but we could be here all day for that. We should always question things, but just because we could, doesn't mean we should.

Wow! That one made my head hurt;) I guess what comes to mind immediately for me here, is where do we draw the line between what should and shouldn't be questioned? At what point do we say that discovery is the wrong thing to do? This applies to so much, but in the terms of time travel: If time travel is possible, shouldn't we try to figure out how? Or, maybe a better way to ask that: Wouldn't we try to figure out how? The one thing that you can say about human nature, is that we are collectively dissatisfied with the idea that we shouldn't know something. That has historically been more of an invitation than a deterrant.Permalink

But if time is a dimension (something we all seem to agree on, except for the fact that I am the only one who has an agnostic approach to the number of possible dimensions themselves), it would not have any paradoxes.

If time is a dimension, all time is all-present and all the future and the past and now already exist.

Meaning if someone would be to travel back in time, that has "already happened", making it possible to invent a time machine by travelling back in time and telling yourself how to do it.

Also, about my acceleration hypothesis: I did not speak about any speed. I was speaking about acceleration - meaning from 0 to like 0.000...01 m/s in a really tiny amount of time, amking it the greatest possible acceleration, just a really short one.

Quoting Deus "Big D." Otiosus
But if time is a dimension (something we all seem to agree on, except for the fact that I am the only one who has an agnostic approach to the number of possible dimensions themselves), it would not have any paradoxes.

If time is a dimension, all time is all-present and all the future and the past and now already exist.

Meaning if someone would be to travel back in time, that has "already happened", making it possible to invent a time machine by travelling back in time and telling yourself how to do it.

Also, about my acceleration hypothesis: I did not speak about any speed. I was speaking about acceleration - meaning from 0 to like 0.000...01 m/s in a really tiny amount of time, amking it the greatest possible acceleration, just a really short one.

P.S.: Found that maximum acceleration.

Now there's an interesting thought. I have to say, I agree. Logically, if we look at time as a dimension of any kind (I hope somewhere here you've all acknowledged that "Dimension" has multiple similar meanings), then it is likely linear in some way. Many fictions try to take the idea of Linear time and tell you it is false (Dr Who's "Wibbly Wobbly Timey Wimey stuff" quote). However, it is highly likely that time is a linear progression and is relative to each person. Thus each individual has their own timeline which runs parallel to the timeline of the universe, which marches ever closer to its destruction. Thus time travel is either pre-ordained, or totally impossible. It's either definitely going to happen, or it isn't. I'm hoping that (Unless I get to be the Time Traveller), that it doesn't happen.Permalink

Quoting Deus "Big D." Otiosus
As much as "timeline" is concerned, time-travel is perfectly safe.

Assuming that time travel is possible, I would tend to agree with you, but just out of curiosity, (because I'm interested to see how close you and I are on this), in reference to your earlier statement about paradoxes: I agree that going back in time and telling yourself how to achieve time travel would be no threat, in the case of a possible time anomaly where time deviates cyclically from a linear flow, but remains fixed in that point on the timeline. A form of a consistent causal loop. But, in your opinion, how does your view on paradoxes compensate for the classic version of the Grandfather Paradox? Permalink

Quoting Tim C
Assuming that time travel is possible, I would tend to agree with you, but just out of curiosity, (because I'm interested to see how close you and I are on this), in reference to your earlier statement about paradoxes: I agree that going back in time and telling yourself how to achieve time travel would be no threat, in the case of a possible time anomaly where time deviates cyclically from a linear flow, but remains fixed in that point on the timeline. A form of a consistent causal loop. But, in your opinion, how does your view on paradoxes compensate for the classic version of the Grandfather Paradox?

I'm not the one you wanted to reply, but I feel like weighing in:
I believe that the Grandfather Paradox is impossible in a linear-based timeline. If one were to travel back in time, as I stated previously, this would have been a pre-ordained occurrence. Thus, one would have to have been born in order for time travel to be achieved. Also, who would be foolish enough to kiIl their own grandfather?Permalink

Quoting Reaper the Ultimate .
I'm not the one you wanted to reply, but I feel like weighing in:
I believe that the Grandfather Paradox is impossible in a linear-based timeline. If one were to travel back in time, as I stated previously, this would have been a pre-ordained occurrence. Thus, one would have to have been born in order for time travel to be achieved. Also, who would be foolish enough to kiIl their own grandfather?

Strange. My reply went to Big D. I don't know why it would say that I replied to you on your end. In fact, I was in the process of replying to Big D when you made your previous statement. Maybe there's some weird time loop and I replied to you in the future. I guess I better do that before I cause any great rips in the universe;) Thanks for weighing in, though, Reaper.

But one note: We could go on forever on the subject of foolishness and who's guilty of it. I'm sure that if time travel were possible we could find one person "foolish" enough to kill his own grandfather. However, I agree with your assessment of pre-ordained occurrences, provided, of course, that every moment in time is fixed and cannot be changed.Permalink

Quoting Tim C
Strange. My reply went to Big D. I don't know why it would say that I replied to you on your end. In fact, I was in the process of replying to Big D when you made your previous statement. Maybe there's some weird time loop and I replied to you in the future. I guess I better do that before I cause any great rips in the universe;) Thanks for weighing in, though, Reaper.

But one note: We could go on forever on the subject of foolishness and who's guilty of it. I'm sure that if time travel were possible we could find one person "foolish" enough to kill his own grandfather. However, I agree with your assessment of pre-ordained occurrences, provided, of course, that every moment in time is fixed and cannot be changed.

If time travel changes history, that only means time is at least two-dimensional. I will do some math on that, but I am not sure if even that is possible.Permalink

Quoting Tim C
Wow! That one made my head hurt;) I guess what comes to mind immediately for me here, is where do we draw the line between what should and shouldn't be questioned? At what point do we say that discovery is the wrong thing to do? This applies to so much, but in the terms of time travel: If time travel is possible, shouldn't we try to figure out how? Or, maybe a better way to ask that: Wouldn't we try to figure out how? The one thing that you can say about human nature, is that we are collectively dissatisfied with the idea that we shouldn't know something. That has historically been more of an invitation than a deterrant.

What I meant was that we SHOULD try to explore. Humans have an insane drive to want to know more about anything and everything to infinite possibilities. But we can't truly grasp infinity, as we are only human. So there are some things that we can and should delve into further, but some things aren't always possible/safe/humane, etc. at least in our universe or however you term it. We have knowledge only based on experience in OUR world, Earth. Yet there are things that we can come up with or think about that are totally farfetched for how we interpret our current human surroundings, but could possibly be possible...just not for us. For example, humans trying to understand the creation of the universe if you will. If you believe in a higher power, you may think that there is a god that created what we interpret as our surroundings, or 'the universe'. However, human experience with anything on Earth tells us that there is a beginning to something. I've used this example before, but a tree comes from a seed and said seed came from a previous tree. And heck, that's great and I think we can all agree on that. But to most, that's not good enough. What about the original tree with the first seed? Where did that tree come from? And what made the thing that made the tree? We want to trace things back and forth indefinitely, but seeing as we're only human we really can't. I know this is a bit off track from time-travel, but I think it falls under a similar reasoning. Sure we can use science and past knowledge to get far, but only to an extent. Such as the atheist reasoning for the creation of the universe. Where did that first speck of matter come from? What is the origin of existence? We should always question everything, but the problem with humans is we're never satisfied. Which is also our strength. So we may be trying to figure out time travel for eternity, which is a bit ironic. Permalink

Quoting Deus "Big D." Otiosus
If time travel changes history, that only means time is at least two-dimensional. I will do some math on that, but I am not sure if even that is possible.

Would it change history? When you start talking about time travel, is anything history? Can anything be changed? We'll never know, unless we can look into a parallel universe which we can alter while we remain rooted in an unchanged timeline.Permalink

Quoting LukeClarenceVan The Revanchist
Would it change history? When you start talking about time travel, is anything history? Can anything be changed? We'll never know, unless we can look into a parallel universe which we can alter while we remain rooted in an unchanged timeline.

Well, I mean, we are assuming that one event must lead to another. What about this possibility: (which may have been brought up; I dunno as I haven't really been following the group like I should be :-/ that is, what about creating another alternate universe (like in Star Trek)? I mean, maybe each eventuality leads to another universe, in which every possible thing that could happen, does. Right now, in this universe, I am typing a comment to LukeClarenceVan. In another, I might be commenting on my new USS Cole. In another, I could be eating a sandwich. In another, I could be, I dunno, hanging off the side of an armed helicopter; in short, anything possible, is carrier out.....Permalink

Quoting Achintya Prasad
Well, I mean, we are assuming that one event must lead to another. What about this possibility: (which may have been brought up; I dunno as I haven't really been following the group like I should be :-/ that is, what about creating another alternate universe (like in Star Trek)? I mean, maybe each eventuality leads to another universe, in which every possible thing that could happen, does. Right now, in this universe, I am typing a comment to LukeClarenceVan. In another, I might be commenting on my new USS Cole. In another, I could be eating a sandwich. In another, I could be, I dunno, hanging off the side of an armed helicopter; in short, anything possible, is carrier out.....

I fully support that theory. However, I'm operating on the basis that each universe is a separate entity and that if you go back in time and change something in yours, that will affect yours. (Of course, it will create more universes, but you won't be aware of them.) Permalink

Quoting LukeClarenceVan The Revanchist
I fully support that theory. However, I'm operating on the basis that each universe is a separate entity and that if you go back in time and change something in yours, that will affect yours. (Of course, it will create more universes, but you won't be aware of them.)

Well, I'm thinking that the effect will be on your own; I mean, where else will it go? I think we can establish there will be an effect, but the question is, where will that effect go? I say a new universe.Permalink

Quoting Achintya Prasad
Well, I'm thinking that the effect will be on your own; I mean, where else will it go? I think we can establish there will be an effect, but the question is, where will that effect go? I say a new universe.

So are you saying that we each have our own timeline's, and one of our decisions merely branches our own timeline, rather than creating an entirely new parallel universe?Permalink

Quoting LukeClarenceVan The Revanchist
So are you saying that we each have our own timeline's, and one of our decisions merely branches our own timeline, rather than creating an entirely new parallel universe?

Both. A decision extends our timeline, and creates a million new ones, depicting each and every possible decision we could make.

I make it seem as if we actually control time; rather, though, even tiny movements in our muscles affect the universe, even if the effect is impossibly small. Making a decision, like, say, walking to a vending machine, may have an effect....Permalink

Quoting Achintya Prasad
Both. A decision extends our timeline, and creates a million new ones, depicting each and every possible decision we could make.

I make it seem as if we actually control time; rather, though, even tiny movements in our muscles affect the universe, even if the effect is impossibly small. Making a decision, like, say, walking to a vending machine, may have an effect....

I think I'm catching on here. What you are saying is that something has to happen in each infinitesimal moment, but there are an infinite number of possibilities of what that something may be. The idea here is that there is a new universe to represent what would happen in each scenario if each particular something took place. In terms of time travel, if a traveler were to go back in time and make something happen contrarily to what happened in his own universe, he wouldn't necessarily be changing the past, just jumping timelines, if you follow me. To go back to his present day to see the effects of the change would end up being the present in his new timeline, or universe, as it were? This is an explanation that has been toyed with by physicists. Completely far-fetched, but I don't see how it could be ruled out as impossible.Permalink

Quoting Tim C
I think I'm catching on here. What you are saying is that something has to happen in each infinitesimal moment, but there are an infinite number of possibilities of what that something may be. The idea here is that there is a new universe to represent what would happen in each scenario if each particular something took place. In terms of time travel, if a traveler were to go back in time and make something happen contrarily to what happened in his own universe, he wouldn't necessarily be changing the past, just jumping timelines, if you follow me. To go back to his present day to see the effects of the change would end up being the present in his new timeline, or universe, as it were? This is an explanation that has been toyed with by physicists. Completely far-fetched, but I don't see how it could be ruled out as impossible.

Yeah, you got the gist of it.

I can think of another way for why it *might* be a viable solution: matter and anti-matter. Physicists are, troubled, to say the least, about anti-matter. In my model of the universe (actually, someone else probably came up with before I did, but yah know) in at least half these parallel universes, you have a universe of just, anti-matter. Why? Because you would be balancing out the universe. Each time a universe in which matter exists appears, another one is created, with the same possibilities only, at the end, anti-matter is created. Permalink

Quoting Achintya Prasad
Making a decision, like, say, walking to a vending machine, may have an effect....

Every minute decision you make does affect you, but I see no reason to believe that it would create another dimension where it happened differently.

Also, someone mentioned travelling to the future earlier and how it wouldn't have paradoxical effects. But you have to consider that YOUR future is also someone else's past. It could create a different past for them.Permalink

Anyone thought of it in the sense that if you get to a paradox, the principle is wrong?

In a system where time "flows", there are so many mistakes, that they prove it to be wrong. And when you accept a dimensional system, please stop using flowing system, because using one of those two systems excludes the other by definition.Permalink

Quoting Medieval Guy
Every minute decision you make does affect you, but I see no reason to believe that it would create another dimension where it happened differently.

Also, someone mentioned travelling to the future earlier and how it wouldn't have paradoxical effects. But you have to consider that YOUR future is also someone else's past. It could create a different past for them.

As far as the multiverse is concerned, there is no evidence to dispute it and it is a well-known theory. Although I do consider this possibility hard to believe, to be fair, we can't actually consider it impossible until some evidence is turned up to prove it as such.

And a temporal paradox deals with going to the past and doing something that will negate the possibility of going to the past, thereby making it impossible to do that something, like the Grandfather Paradox. To change something in the future would not cause a paradox, all it would do is change the future, (if time can be changed at all), albeit someone else's past, (I see what you're saying), but it wouldn't cause the inconsistency that defines a paradox.Permalink

Quoting Deus "Big D." Otiosus
Anyone thought of it in the sense that if you get to a paradox, the principle is wrong?

In a system where time "flows", there are so many mistakes, that they prove it to be wrong. And when you accept a dimensional system, please stop using flowing system, because using one of those two systems excludes the other by definition.

Flowing system is usually a good model, because everyday objects travel through time in the same direction at roughly the same rate.
But you're right, thinking about time as a dimension gives a superior understanding to things like time travel than the flow model. Permalink

Quoting Deus "Big D." Otiosus
Anyone thought of it in the sense that if you get to a paradox, the principle is wrong?

In a system where time "flows", there are so many mistakes, that they prove it to be wrong. And when you accept a dimensional system, please stop using flowing system, because using one of those two systems excludes the other by definition.

Flowing system is usually a good model, because everyday objects travel through time in the same direction at roughly the same rate.
But you're right, thinking about time as a dimension gives a superior understanding to things like time travel than the flow model.

Actually, considering the big bang theory, dimensional system can answer that question too.

But let me ask you a question. How do you know everything is "moving through time" at the same speed?Permalink

The Doppler Effect has proven that the universe is constantly expanding. With that in mind, logic would tell us that the universe had to have started out as something unimaginably small and unimaginably dense. That goes a long way to answering the question of the Big Bang. Was that just a side point? Otherwise, I'm having trouble relating that to time travel.Permalink